Major air leak at Fan shutter-stat

So I started the truck up today to go over some things. Reset the CTIS and I'm still getting the 4 light error (leaking tire somewhere?). The truck aired up, but I noticed the secondary was having a rough time and coming up slowly. Then I noticed a strong hiss and traced it to the Shutter-stat. There is a small vent hole on the back of it and a strong stream of air was coming out, steadily draining the secondary air system.


Would this be a problem with the shutter-stat itself, or maybe a bad valve up-stream that's dumping air into it? I'm assuming if I remove the stat, a lot of coolant will come out. Trying to avoid making that mess right now, it's coooold.

OK I found a good thread with the same issue I am having. http://www.steelsoldiers.com/showthread.php?83932-Actuator-Air-Fan-Clutch-for-M923a1/page5

So now a related question: Could I pull the end off and take the guts out without loosing any coolant? Is the sensor end sealed off from the air end? Seems like it would have to be.

OMG! I just looked up what a new one costs. You've got to be kidding me!! Are they gold plated?!

You'll need to drain some coolant to get it off. I'd just drain into a cean bucket from the radiator. Remove, clean, and lube the shutter stat, replace, then pour the coolant back in.

I need to clean mine again. It's starting to stick open again.

And while your in there you should replace the O rings.

Yes you can service in place without removing or loosing any fluid.

Floridianson said:

Yes you can service in place without removing or loosing any fluid.

Click to expand...

There is an O-ring behind the jam nut on the thermal capsule end. If that fails it will pressurize your cooling system and cause problems. There is also a spring loaded sliding tube on that end that needs to move freely. Best to remove it completely and service both ends.

As said above, just remove some coolant into a clean container from the radiator drain, remove the shutterstat and add the coolant back after installation.

Note: Don't mess with the tip/cap of the capsule. It's fragile and not serviceable.

Thanks all, I'll do it right and pull it, replace all O-rings. Hopefully that takes care of it.

Had a few extra minutes and decided to pull the guts out leaving the front part in the truck. I found the obvious problem.

The big O-ring was very hard and flattened on the outside surface. It wasn't broken, I did that removing it. The 2 smaller ones look fine, but I'll replace them too just to be safe. I noticed wrench marks on the valve body, so someone already was in the thing before. Can't get the parts till Friday of course.

Can not believe what a replacement costs. There's nothing to it, unless the sensor end is some space-age technology.

I'll pull the rest of it out of the radiator pipe and service it later if this gets me by. I hate messing with coolant a stuff like that in the winter.

Your welcome.

Looking at the pics from the other thread I see my valve is slightly different. My needle valve in the end cap is just plastic (the white pointy cone). In the others it is brass. I would be seriously ticked-off if I had to pay $250 for a new valve because that little $.05 piece failed.

Since there is no sign of any coolant in the valve body, I'm going to assume the other O-ring on the sensor end is good.

The parts in my picture are from my spare. It has the plastic plunger. The one in my truck has the brass plunger. The brass plunger has an O-ring that seals the hole, which is replaceable. I agree that the brass is a better design than the plastic.

Anyone have any luck replacing the large O-Ring? I don't think it's a standard size. I'm having trouble matching it up.

I've emailed the manufacturer, Evans Tempcon, to see if I can get that seal/o-ring.

Todds
i looked for one for several days...it's not standard or metric.....
It is between a 205 & 206 metric in all 3 dimensions (id,od,width)
I finally located one at a hydraulic packing and insulation company.
a little snug but lubed it and ran truck on and off under load and it works fine
cost me .80 cents. I took old one in to place and it took a bit but we matched it up

Thanks, that's what I'm finding it's in-between everything. Hopefully I'll hear something back from Evans. I'll try a hydraulic shop next week.

Worst case I can go pick up another and mail it to you.
letme know how you make out

So, I finally heard back from Evans. They forwarded my email to a parts distributor, I CAN get the seal o-ring from them. They are $20.95 each (plus shipping), which is much better than $245 for a whole new actuator! I wasn't able to call today, but will call tomorrow and order one. I will post up the contact info, once I get it ordered and have it in my hand to verify.

Part was ordered 01/06/2015. Apparently it's a kit that contains all the O-rings.

Fail!

Arrrgh, finally got the parts from Evan's. They weren't sure what O-ring to send so they send me one of each they showed for the actuator. So I ended up with 4 different O-Rings ($5 ea) and none of them are the one I need!

Back to the drawing board. And I still have a dead-lined truck. I'm going to try to call them and actually talk to someone this time and explain what I need. Very frustrated at this point.

Try these 2 part numbers at your local Cat house. I haven't had time to fully reassemble and test my spare with these installed but test fitting felt real good. The larger one is $5 and the smaller one is less than a buck. You'll need 2 of the smaller one.

Using multiple O-rings to determine nominal size for the larger one, I've come up with standard dimensions that should work. Try an O-ring with these dimensions: 1/2" ID x 3/4" OD x 1/8" CS. The cross sectional dimension seems to be the part that makes this a not so common size.





I have both of these O-rings installed but it'll be this weekend before I can completely assemble and test for proper function.

Using a micrometer on the worn one, I come up with 2.56mm thick and 12.99mm inside diameter. I found a listing for a metric one 3mm x 13mm. I'm trying to get my hands on one to test it.

The original is also not a true O-ring. It's kind of squared off. I think it's also a harder, almost plastic, material than most O-rings I can find.

The smaller ones are a standard size. Can't remember size off the top of my head, but found them in a standard kit.